package leetcode.onehundred;

import java.util.ArrayList;
import java.util.List;

//94. 二叉树的中序遍历
public class InorderTraversal {
    public List<Integer> inorderTraversal(TreeNode root) {
        List<Integer> res = new ArrayList<>();
        inorder(root,res);
        return res;
    }

    private void inorder(TreeNode root, List<Integer> res) {
        if (root==null){
            return;
        }
        inorder(root.left,res);
        res.add(root.val);
        inorder(root.right,res);
    }
}
class TreeNode {
      int val;
      TreeNode left;
      TreeNode right;
      TreeNode() {}
      TreeNode(int val) { this.val = val; }
      TreeNode(int val, TreeNode left, TreeNode right) {
          this.val = val;
          this.left = left;
          this.right = right;
      }
  }